Stitch-forming mechanism of a sewing machine



March 26, 1963 TOSHIO TATEISHI STITCH-FORMING MECHANISM OF A SEWING MACHINE Filed Aug. 4, 1959 8 Sheets-Sheet 1 INVENTOR TOSHIO EA EIHI O f4 ATTORNEY March 26, 1963 TOSHIO TATEISHI 3,

STITCH-FORMING MECHANISM OF A SEWING MACHINE Filed Aug. 4, 1959 a Sheets-Sheet 2 BYW KM ATTORN EY March 26, 1963 TOSHIO TATEISHI 3,

' STITCH-FORMING MECHANISM OF A SEWING MACHINE Filed Aug. 4. 1959 s Sheets-Sheet 3 SH SP N W a (/77 r V 14! g m m T RH R TN INVENTOR I ATTORNEY March 26, 1963 TOSHIO TATElSHl 3,

STITCH-FORMING MECHANISM OF A SEWING MACHINE Filed Aug. 4, 1959 8 Sheets-Sheet 4 RH R TB TN INVENTOR o5 H10 Dram ATTORNEY March 26, 1963 TOSHIO TATElSHl 3,082,722

STITCH-FORMING MECHANISM OF A SEWING MACHINE Filed Aug. 4, 1959S a Shets-Sheet 5 S T Fig. 9 N Fig. /0 N [X E 3 L X1 P R 8 RH p Fig. .9

Illllllllllllil'llllllil I IIIIIIIIIIHIHIIIIHH I IIIIIIILLIIHIIII'IIIIIJ I Llllllllllllllllllllllfl INVENTOR TO SHIO TAIEI SHI ATTORNEY TOSHIO TATElSHl March 26, 1963 STITCH-FORMING MECHANISM OF A SEWING MACHINE 8 Sheets-Sheet 6 9 5 9 1 4 L. u A d e l i F INVENTOR res 1m firi/su/ 47 X M ATTORNEY March 26, 1963 TOSHIO TATElSHl 3,082,722

STITCH-FORMING MECHANISM OF A SEWING MACHINE Filed Aug. 4, 1959 8 Sheets-Sheet 7 1 Fly. /4 N XV XV L. J

S RH R INVENTOR TO SHIO TATEI SHI ATTORNEY March 26, 1963 TOSHIO TATEISHI 3,082,722

' STITCH-FORMING MECHANISM OF A SEWING MACHINE Filed Aug. 4, 195 8 Sheets-Sheet 8 SP RH INVENTOR 705/00 TATE/6M BYW ATTORN EY tates atent *Ofiice 3,082,722 Patented Mar. 26, 1963 3,082,722 STITCH-FGNG MECHANISM OF A SEWING MACHINE Toshio Tateishi, Shinkai-cho, Mizuho-ku, Nagoya, Japan, assignor to Nihon Mishin Seizo Kahushiki Kaisha, Nagoya, Japan, a corporation of .Iapan Filed Aug. 4, 1959, Ser. No. 831,566 Claims priority, application Japan Aug. 8, 1958 1 Claim. (Cl. 112-181) This invention relates to a lock-stitch sewing machine. More particularly it relates to improvements in a sewing machine of the low speed lock-stitch type, i.e., sewing machines for domestic use, comprising a vertically reciprocating thread-carrying needle, a loop-taker which forms lock-stitches in cooperation with said needle, and a feedmechanism capable of feeding the work both forward and rearward, wherein the aforesaid loop-taker is made to be rotated or oscillated around a substantially horizontal fixed axis lying within a perpendicular plane which is parallel to the line of feed of the aforesaid work and in the proximity of the vertical reciprocatory line of the aforesaid needle, and the eye of the aforesaid needle through which passes the needle thread is bored in the same direction as the aforesaid feed. In recent years, it is demanded of sewing machines for domestic use that they not only be capable of forming straight line stitches but also form zigzag stitches in synchrony with the vertical reciprocatory movements of the needle for making it possible to accomplish various types of ornamental sewings. Hence, the zigzag sewing machines account for a substantial proportion of the sewing machines for domestic use.

However, of these universal sewing machines that are capable of zigzag stitches those in which the loop-taker being disposed in a fixed position and made to either rotate or oscillate greatly predominate due chiefly to economic reasons, and those in which the loop-taker is made to move laterally together with the needle are gradually going out of existence.

However, since in a zigzag sewing machine which forms zigzag stitches by disposing a loop-taker having a horizontal fixed axis in a fixed position and causing it to rotate or oscillate while oscillating the needle only there is a need on account of its characteristics to oscillate the needle transversally to the line of feed of the work and to seize the loop of needle-thread at both of the extremities of the oscillation of the needle, it is necessary to dispose the axis of the rotation or oscillation of the loop-taker in a substantially perpendicular plane parallel to the line of feed and in the proximity of the vertical reciprocatory line of the needle. This is a necessary requirement for insuring that that part of locus of the movement of the loop-seizing beak of the loop-taker close to the needle traverses the line of feed. Now when the production of this type of zigzag sewing machine becomes very substantial, it is natural from an economical concept to give consideration to the matter of interchangeability between the zigzag sewing machines and the straight stitch machines by adopting in the production of the latter a structure such as described above. However, while it is possible to obtain a beautiful line of stitch, as shown in FIG- URE 12, when straight stitching was performed with this type of sewing machine while feeding the work in the normal direction away from the operator, when the feed is in the opposite direction, that is, towards the operator, the line of stitches, as shown in FIGURE 3, is very unsat isfactory in appearance and is of no utility whatsoever.

Therefore, an object of this invention is to provide for an improvement in the line of stitch in case straight stitching is performed in a sewing machine as constructed above, namely a sewing machine comprising a loop taker made to move in a fixed position and a vertically reciprocating thread-carrying needle which in cooperation therewith form lock-stitches, wherein the locus of movement of the loop-seizing beak of the loop-taker is made to be in a plane traversing the line of feed of the work, and the eye of the aforesaid needle through which the needle thread passes is bored in the same direction as the aforesaid line of feed, particularly, in case the work is fed in reverse, i.e., by improving the stitches when the direction of feed is toward the operator instead of the normal feed away from the operator to make possible the forming of accurately perfect lock-stitches regardless of whether the fed is forward or rearward.

Another object of the invention lies in achieving the above-described object by the act of simply improving the relationship between the axis of the thread eye and line of direction of the feed.

Other objects and functions of this invention and the advantages to be derived from this invention will be clarified by the following description of the invention.

Next, while referring to the drawings, the features of this invention will be described while comparing the stitchforming mechanism of the conventional machine with the specific embodiments of the machine of thi invention.

FIGURE 1 is an illustration of the essential parts of a conventional machine with which the present invention will be put into practice, being a front view looking in the feed direction taken along the perpendicular plane passing through the axis of the needle hole of the needle plate, and shows the relationship between the needle, the feed dog, and the loop-taker with all those parts not connected with this invention being omitted to facilitate the understanding of the invention.

FIGURE 2 is an enlarged sectional view taken along line II--II of FIGURE 1. FIGURE 3 is a plan view of the appearance of the stitch formed when the machine of FIGURE 1 is fed in reverse, i.e., when the work is fed so as to approach the operator. FIGURE 4 is a perspective view of the essential parts, showing by means of a section of a material the structure of the stitches that are formed when the machine shown in FIGURE 1 is fed in reverse. FIGURE 5 is a similar view as FIG- URE 4 in which is shown the state where another new stitch has been completed after the needle N in FIGURE 4 has made one complete up-and-down cycle from the position shown in FIGURE 4. FIGURES 6a, 6b, and 6c show in successive stages theformation of a stitch, resulting from one descending and ascending cycle of the needle N of FIGURE 5 completed from the position shown in FIGURE 5, and correspond to the sectional view taken along line VIVI of FIGURE 1; FIGURE 611 being that when the loop-seizing beak has seized the needle-loop formed in the vicinity of the needle N, FIGURE 6b showing when the loop which has been seized by the loop-taker of FIGURE 6a has been spreaded to its maximum size, and FIGURE 6c showing where the loop has been drawn up to a position just before the stitch is completed. FIG- URES 7a, 7b, and 7c show in successive stages the formation of stitches, resulting from needle N of FIGURE 4 descending and ascending from the position shown in FIGURE 4; FIGURES 7a, 7b, and 70 corresponding to FIGURES 6a, 6b, and 60, respectively.

FIGURE 8 is a view corresponding to FIGURE 1 showing an illustration of the mode of operation of this invention, FIGURE 9 being an enlarged sectional view taken along IX-IX line of FIGURE 8, and FIGURE 9a being an enlarged sectional View of the needle taken along the same line, while FIGURE 10 is a view corresponding to FIGURE 1 with the loop-taker being omitted showing another embodiment of this invention, FIGURE 3 11 being a sectional view taken along line XIXI of FIGURE 10, and FIGURE 11a being an enlarged sectional view of the needle taken along the same line. FIGURE 12 is a plan view of the appearance of the stitches obtained by the machine in accordance with this invention when the direction of feed was reversed.

The drawings of FIGURES 13a to 13c show the manner of stitch formation when the feed of the embodiment of the sewing machine as shown in FIGURES 8 to was in reverse; FIGURES 13a, 13b, and 130 corresponding to FIGURES 6a, 6b, and 6c, respectively. FIGURE 14 shows another embodiment corresponding to FIG- URE 10, and FIGURE 15 being a sectional view taken along line XVXV of FIGURE 14, and FIGURE 15a being an enlarged sectional view of the needle taken along the same line.

As shown in FIGURES 1 and 2, the conventional machines of this type were those in which the axis e-e of the thread eye E of the needle N was included in a plane 'SSff that is parallel to the line of feed F and includes the straight line 8-8 which is not only parallel to the line of reciprocation of the needle N but also passes through the point P of the needle. However, in these machines, the line of stitches obtained, when the direction of feed was reversed, was very poor in its appearance as shown in FIGURE 3, and was such that it could not be put to practical use.

I have made a study of conditions of stitch formation of this type of machine when the feed of direction was reversed, and have succeeded in removing the cause of the aforementioned irregularity of the line of stitch and have obtained a line of stitch with excellent appearance and regularity.

As a result of close observation of the conditions of the stitch formation when the feed was in the reverse direction, I found that the needle-thread TN between the thread eye E and the stitch in the cloth W, as shown in FIGURE 4 to 7a, 7b and 7c, was very unstable, moving either to the right or left of the needle N, and moreover that its movement was influenced chiefly by the stitch formed immediately before; and thus, as shown in FIG- URES 4 and 5, that the next stitch formed becomes a different type than that already formed immediately before.

In the first place, that there are two types of stitches, i.e., the so-called perfect stitch and hitch-stitch, was heretofore widely known. Normally, the line of stitch of the aforesaid perfect stitch presents a g shape, and on the other hand, the hitch-stitch presents a Z shape. In the drawings, the perfect stitch has been indicated as SP while the hitch-stitch has been indicated as SH.

While a perfect stitch that would present a Z shaped appearance and a hitch-stitch that would present a shaped appearance, which both are completely opposite that of the aforementioned line of stitches can be easily presumable from experience, unless the stitchforming mechanism for forming the Q shaped perfect stitch is employed, the g hitch-stitch cannot be formed. Moreover, it is possible to form a 9 shaped perfect stitch and a shaped hitch-stitch with this stitch-forming mechanism. And since a g shaped hitch-stitch can only be formed by a stitch-forming mechanism for forming a Z shaped perfect stitch, the description hereinafter will be only that of a common stitch-forming mechanism for forming a shaped perfect stitch and a Z shaped hitch-stitch, while the stitch-forming mechanism for forming a Z shaped perfect stitch and a shaped hitch-stitch shall be understood from the foregoing common stitch-forming mechanism.

As can be seen from the drawings, in the above type of machines, when the direction of feed is in the reverse direction, it is usual that the formation of a hitch-stitch SH is followed by a perfect stitch SP and that after a perfect stitch SP, a hitch-stitch SH is formed. It

can be observed that the cause for this is due to the fact that when the needle N descends to form the next stitch after a perfect stitch SP, it passes to the left of the needle-thread TN, while when the needle N descends to form the next stitch after a hitch-stitch SH, it passes to the right of the needle-thread TN.

And when further observations were carefully made to ascertain the reasons for the changes in the type of stitches, results as shown in FIGURES 6 and 7 were obtained. The drawings of FIGURE 6 illustrates the manner in which a hitch-stitch is formed when the needle N descends further from its position shown in FIGURE 4, while those of FIGURE 7 illustrates the manner in which a perfect stitch is formed with the. further descent of the needle N from its position shown in FIGURE 5. In the drawing, H is the loop-taker that oscillates and HB, the loop-seizing beak formed on the aforesaid looptaker H, which 1oop-seizing beak is capable of seizing the loop of the needle-thread carried by the needle on the side of said needle away from the operator. B is the bobbin case for holding the bobbin-thread TB, R, the needle plate, RH, the needle-hole through which the aforesaid needle N passes and FD is the feed dog which is capable of feeding the work towards or away from the operator.

The cause for the change in the position where the needle N passes with respect to the needle-thread is considered to be due to the following fact.

In case the stitch formed immediately before is a perfect stitch SP, at the final stages where the stitch SP is being formed when the needle N is near its highest point of movement, while the needle-thread TN is stretched by the needle-thread take-up mechanism (not shown) between the thread eye E of the needle N and the end of the above stitch SP located directly below the needle N, the needle-thread TN, being drawn out from a spot deviating to the right of the middle of the stitch SP, the bottom of the needle-thread is inclined to the right with respect to a plane S-S-fi-f that is parallel to the line of feed F and includes the straight line 8-3 which is not only parallel to the line of reciprocation of the needle N but also passes through the point P of the needle N. Hence, by the action of the feed dogs FD (opposite to the arrow of the direction of feed F), with the descent of the needle N, that part of the needlethread TN between the thread eye E and the cloth W is guided along in contact with sloping right side of the needle N and assumes the state as shown in FIGURE 4. On the contrary, in case the stitch formed immediately before is a hitch-stitch SH, it is exactly the opposite. Namely, at the final stages where the stitch SH is being formed when the needle N is near its highest point of movement, the needlethread TN is stretched between a point, which deviates to the left of the stitch SH, and the thread eye E of the needle N; and the needle-thread TN is guided to the sloping left side of the needle N by the action of the feed dogs FD (opposite to the arrow of the direction of feed F) with the descent of the needle N.

Therefore, in order to devise a means so that the above needle N would pass without fail on one side of the needle-thread when it makes its descent gradually from the highest point of its movement, I engaged in much study and, as a result, was able to discover a sure and most simple method for accomplishing the foregoing.

While the aforesaid inclination of the needle-thread TN is very slight, to cause that part of the needle-thread TN at an equal height as the point P of the needle N to lean to one side of said point P at all times regardless of the type of the stitch formed immediately before it very easily accomplished. As shown in FIGURES 9a and 11a, this was made possible by causing a slight deviation h of the point of inter section of the center line ee of thread eye E of the needle N and the circumference of said needle N from the plane S-S-f-f parallel to the line of feed F in which plane lies the straight line 5-8 which is parallel to the line of the vertical reciprocation of the needle N that passes through the aforesaid point P. The reason for this is due to the fact that generally when the needle N is at the highest point of its movement, as compared with the distance between the point P and the cloth W, the distance between the thread eye E and the point P is small, and at the same time the deviation from the center line of the stitch is very minute. Thus the deviation h of the aforesaid center line ee 0f the thread eye E with respect to the aforesaid perpendicular plane SSff affects very greatly the aforesaid relationship, such as described above, of the needle to the needle thread, consequently, as described hereinabove, causing the needle thread TN to incline to one side of the point P of the aforesaid needle N, whereby it is possible to prevent the formation of irregular line of stitches.

To accomplish the foregoing, the present invention, which comprises a vertically reciprocating thread-carrying needle, a loop-taker which forms lock-stitches in cooperation with said needle, and a feed mechanism capable of feeding the work both forward and rearward, wherein said loop-taker is made to be rotated or oscillated around a substantially horizontal fixed axis lying within -a perpendicular plane which is parallel to the line of feed of the aforesaid work and in the proximity of the vertical reciprocatory line of the aforesaid needle in order that said looper-taker can seize with its loop-seizing beak the loop of the needle-thread carried by the needle on the side facing or the side away from the operator, and the eye of the aforesaid needle through which passes the needlethread is bored in the same direction as the feed, is characterized in that the center line of the eye of the aforesaid needle is made to either intersect with an acute angularity a plane parallel to the line of feed in which plane lies the vertical reciprocatory line of the aforesaid needle that passes through the point of the needle, or deviate a given distance from said plane, whereby perfect lockstitches are accurately formed whether the work is fed forward or rearward.

When the present invention is embodied in a sewing machine, as shown, for example, in FIGURES 1 and 2 wherein the loop-taker H oscillates around a horizontal fixed axis disposed in a vertical plane SS-ff parallel to the line of feed f-- in which plane lies a straight line S-s parallel to the vertical reciprocatory line of the aforesaid needle in order that the loop-seizing beak HB of the loop-taker H seizes the loop of the needle thread carried by the needle on the side of the needle away from the operator, the axis ee of thread eye E of the needle N may be made either to intersect at an acuate angle of a given angular measure to the aforesaid plane S-S-f-f as shown in FIGURES 8 and 9 or the aforesaid axis e-e may be made to be deviated with respect to the plane S-S-f--f while in parallel thereto as shown in FIGURES 10 and 11, and FIGURES 14 and 15. When, as shown in FIGURES 8 and 9, it is made to intersect atan acute angle of a given angular measure,

in the common sewing machine for family use, the angle most suitable is from about 12 to 25, as has been confirmed by numerous experiments. And in case where the axis of the thread eye has been deviated for a given distance as in FIGURES 10 and 11, and FIGURES 14 and 15, the amount of deviation that is most suitable is from about mm. to mm. Furthermore, in all of these embodiments as shown in FIGURES 8 and 9, 10 and 11, and 14 and 15, the manner of stitch formation when the feed is in reverse takes the course as illustrated in FIGURES 13a to 13c, and the type of stitch formed is not affected by the stitch that has been previously formed. Hence, if the direction of inclination or the direction of deviation of the axis e-e of the thread eye is determined in accordance with the type of sewing machine, chiefly the characteristics of the loop-taker, it is possible to obtain beautiful lines of perfect stitches of shape as shown in FIGURES 12, 13a, 13b and 130.

'As described hereinabove, this invention is that in which by means of a very slight contrivance very large benefits are obtained, and thus is a very effective invention.

What is claimed is:

A stitch-forming mechanism of a sewing machine comprising a vertically reciprocating thread-carrying needle having a single thread eye, a rotary loop-taker having a loop-seizing beak and a bobbin which, in cooperation with said needle, forms lock-stitches, and means for feeding work towards and away from an operator, wherein said loopseizing beak of said loop-taker is movable along a circular pass around a substantially horizontal fixed axis lying within a perpendicular plane which is parallel to the line of feed of the work and in the proximity of the vertical reciprocatory line of said needle, characterized in that said single thread eye, through which the thread carried by said needle passes, is so bored that the point of the thread outlet side at which the center line of said thread eye intersects the circumference of said needle is offset with respect to a plane which is parallel to said line of feed and which passes through the point of said needle and includes the vertical reciprocatory line of said needle, whereby lock-stitches of the same characteristics are accurately formed regardless of the direction of feed of the work.

References Cited in the file of this patent UNITED STATES PATENTS 216,141 Bridge June 3, 1879 360,884 Hutchinson Apr. 12, 1887 1,877,757 Hemleb Sept. 20, 1932 1,988,789 Gricb Ian. 22, 1935 2,652,795 Casas-Robert et al Sept. 22, 1953 2,824,533 Goos-man Feb. 25, 1958 2,862,468 Johnson Dec. 2, 1958 FOREIGN PATENTS 648,879 Germany Aug. 11, 1937 

